WR-134 is the blue arc seen in the image. It is the result of a shock wave emanating from a Wolf-Rayet star. These stars have very strong stellar winds and are extremely hot, with surface temperatures ranging from 20,000K to 210,000K.
Wolf–Rayet stars are evolved, massive stars that have completely lost their outer hydrogen and are fusing helium or heavier elements in the core.
The star causing all this is the brightest star of the crooked group of four, at the center of the radius of the arc, and almost a full circle of glowing gas surrounding it, also identified as a variable star, V1769 CYG

William Optics FLT-91 refractor, Starizona Apex-EDL reducer, ZWO ASI 294MM Pro camera, SkyWatcher EQ6R-Pro mount

27x 300 second 6nm OIII and 21 x 400 sec 6nm H-alpha
4 hours total integration